If you have decided you want to know more about the article, it is time for the second pass. This pass should take about an hour. Read the article again and focus on the main points. Are there specific parts of the paper you’re particularly interested in? What are the main points of the article? With what kind of results do they use to back up these findings?  During the second pass, you focus on the following three points:

1. The figures in the article. Are axes labelled properly? Is the data presented with error bars? These differences will separate well-written, quality research from sub-par work.
2. Read the discussion. What are the main points of the article? Avoid diving into the proofs in too much detail.
3. Check the references. Once you’ve found a number of papers relevant to your research topic you’ll notice many overlapping resources, and a few key (review) articles will keep popping up. Mentally tick off the references you’ve already used, and keep a list of articles you still want to take a look at.

At this point you should be able to shortly summarise the main arguments, with supporting evidence, to someone else. Preferably someone in the same field, your cat or elderly neighbour might be a little lost. After this pass you might notice the paper is badly written or the arguments have poor foundations. In-depth explanations of unfamiliar experimental techniques, acronyms, or one-too-many late nights could also be responsible for you struggling to understand the article. You may choose to stop reading here, or come back to the paper another time. Otherwise, go forth to the third pass.